From 13c557fe823549db75c3dc24c99c46e1c4e1378e Mon Sep 17 00:00:00 2001
From: regnat <rg@regnat.ovh>
Date: Wed, 25 Nov 2020 11:20:03 +0100
Subject: [PATCH] fix the hash rewriting for ca-derivations

---
 src/libstore/build/derivation-goal.cc | 14 ++++++++++++++
 tests/content-addressed.nix           |  9 ++++++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index bf2bad62c..0e4504857 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -3121,6 +3121,20 @@ void DerivationGoal::registerOutputs()
             newInfo0.references = refs.second;
             if (refs.first)
                 newInfo0.references.insert(newInfo0.path);
+            if (scratchPath != newInfo0.path) {
+                // Also rewrite the output path
+                auto source = sinkToSource([&](Sink & nextSink) {
+                    StringSink sink;
+                    dumpPath(actualPath, sink);
+                    RewritingSink rsink2(oldHashPart, std::string(newInfo0.path.hashPart()), nextSink);
+                    rsink2((unsigned char *) sink.s->data(), sink.s->size());
+                    rsink2.flush();
+                });
+                Path tmpPath = actualPath + ".tmp";
+                restorePath(tmpPath, *source);
+                deletePath(actualPath);
+                movePath(tmpPath, actualPath);
+            }
 
             assert(newInfo0.ca);
             return newInfo0;
diff --git a/tests/content-addressed.nix b/tests/content-addressed.nix
index 8ca96d4bf..985220f48 100644
--- a/tests/content-addressed.nix
+++ b/tests/content-addressed.nix
@@ -16,14 +16,16 @@ rec {
   };
   rootCA = mkDerivation {
     name = "rootCA";
-    outputs = [ "out" "dev" ];
+    outputs = [ "out" "dev" "foo"];
     buildCommand = ''
       echo "building a CA derivation"
       echo "The seed is ${toString seed}"
       mkdir -p $out
       echo ${rootLegacy}/hello > $out/dep
-      # test symlink at root
+      ln -s $out $out/self
+      # test symlinks at root
       ln -s $out $dev
+      ln -s $out $foo
     '';
     __contentAddressed = true;
     outputHashMode = "recursive";
@@ -34,7 +36,8 @@ rec {
     buildCommand = ''
       echo "building a dependent derivation"
       mkdir -p $out
-      echo ${rootCA}/hello > $out/dep
+      cat ${rootCA}/self/dep
+      echo ${rootCA}/self/dep > $out/dep
     '';
     __contentAddressed = true;
     outputHashMode = "recursive";